Rhodamine-Based Fluorescent Probe for Highly Selective Determination of Hg(2+)

[Image: see text] The determination of mercuric ions (Hg(2+)) in environmental and biological samples has attracted the attention of researchers lately. In the present work, a novel turn-on Hg(2+) fluorescent probe utilizing a rhodamine derivative had been constructed and prepared. The probe could highly sensitively and selectively sense Hg(2+). In the presence of excessive Hg(2+), the probe displayed about 52-fold fluorescence enhancement in 50% H(2)O/CH(3)CH(2)OH (pH, 7.24). In the meantime, the colorless solution of the probe turned pink upon adding Hg(2+). Upon adding mercuric ions, the probe interacted with Hg(2+) and formed a 1:1 coordination complex, which had been the basis for recognizing Hg(2+). The probe displayed reversible dual colorimetric and fluorescence sensing of Hg(2+) because rhodamine’s spirolactam ring opened upon adding Hg(2+). The analytical performances of the probe for sensing Hg(2+) were also studied. When the Hg(2+) concentration was altered in the range of 8.0 × 10(–8) to 1.0 × 10(–5) mol L(–1), the fluorescence intensity showed an excellent linear correlation with Hg(2+) concentration. A detection limit of 3.0 × 10(–8) mol L(–1) had been achieved. Moreover, Hg(2+) in the water environment and A549 cells could be successfully sensed by the proposed probe.